Frigid weather range (from OVMS)


(system) #1

So with the OVMS module installed, I’m finding out some interesting tidbits about my Twizy, including at which point the low battery warning kicks in.

With just over 100 miles on the clock of Echo, I headed out this morning with my son to test a route for some new teaching I’ll be doing after Easter (I wanted to see if the Twizy could do the route.)

It’s just below freezing here in Bristol, with a wind chill of at least -5. Even with windows, the Twizy is particularly cold!

I covered about 34 miles in total, with some pretty big hills in and around the top end of South Gloucstershire. (And I made some wrong turnings)

The low battery warning kicked in when OVMS said the battery was at 12% SOC. When I got home, these were the readings from OVMS:


Power -6713 +256 Wh. This means I used 6.713 kWh, and recaptured 0.256 kWh from regenerative braking.

Const 49% -2910 +84 Wh. This means I was keeping a constant speed for most of the time, accounting for 2.91 kWh of battery use, and 0.084 kWh regenerated.

Accel 26% -2412 +27 Wh. This is how much of the time I was accelerating, accounting for 2.412 kWh of battery use, and 0.027 kWh regenerated.

Yes, I know there are some figures missing… not sure where they can be accounted for, because they don’t add up! :slight_smile:

However. if the first one is right (and I think it is) then I’ve used 6.7 kWh of energy today on my little jaunt.

Nikki.


(Normsthename) #2

Interesting! :slight_smile:
How do the two range indicators work?
One shows Ideal and the other shows estimated.
How are these calculated?

Andy


(Lightly) #3

So regen doesnt count for much does it


(ecofunkytravel) #4

No, not really. It’s a bit better than I thought, actually - must have been some hills to descend as well as climb. The climbing energy may be the missing 25% on the energy expenditure.


New Side-by-Side Twizy?
(system) #5

A good question, and a great feature of OVMS!

OVMS not only reads the predicted range from the Twizy – which is based on how you’ve been driving recently – but it also allows you to give it an arbitrary figure for how many miles you think you normally get from a full pack.

It’s particularly useful if you live in a really hilly area. For example, my trip this evening to Bath (34 miles round trip, 6.35kWh used, 3 bars and 9 miles remaining) requires me to climb some pretty big hills on my way TO Bath. One (up near Landsdown racecourse) is so extreme that the Twizy slows from 50 mph down to 25 mph as it’s climbing it.

On my outward leg, the Twizy is extremely pessimistic about range, as it assumes my driving will continue to be power-hungry. But because I know I can get about 40 miles on a charge, OVMS gives me a much more realistic range prediction given a specific battery SOC.

I can really recommend OVMS (http://www.fasttech.com/product/1000300) as an awesome addon to your Twizy. It also acts as a tracker, so if the worse happens – or you break down – it’s easy to find your car!

Plus, there’s a version of the app in development which will even use your car’s SOC to get you routed to a nearby charging station!

Nikki.


(Normsthename) #6

On my outward leg, the Twizy is extremely pessimistic about range, as it assumes my driving will continue to be power-hungry. But because I know I can get about 40 miles on a charge, OVMS gives me a much more realistic range prediction given a specific battery SOC.

Very Interesting. :slight_smile:
I have a similar problem with the built in Twizy range estimator.
My house is along a fast road, and the last two miles home is Flat Out.
When I go to work in the morning the estimated range shows anywhere from 28 to 34 Miles.
I drive 8 Miles to work and I get back more miles than I use!
On a warm day and taking it easy the range will upto show 40 Miles when I arrive…
On the return leg I have usually approx. 34 Miles showing and after the 8 Miles back home the range drops like a stone.
I sometimes only have 10 Miles showing when I get home.
Looking at the actual Energy Bar Gauge it shows 6-7 Bars remaining.
Working on 3.5 Miles per bar in Winter, that means approx. 25 miles actual range left.
Now I know how the range estimator works, I don’t panic if it shows a few miles remaining.
I must have a look at OVMS :smiley:

Andy


(system) #7

Hi Andy,

Yes, do! It’s a very neat piece of kit. Later on today, I hope to do a ‘how to’ post for ZCW on installing it in a Twizy :slight_smile:

Nikki.